1. Field of The Invention
Applicant's invention relates to a hammer shaping tool; and, more particularly, to a tool that is designed to correctly shape and voice piano hammers.
2. Background Information
The modern pianoforte, or piano, was developed in the early 1700's when a harpsichord was modified to include an escapement action, which involved depressing a key thereby causing a hammer to strike a string. The piano was later refined to include repetition, or double-escapement, action which is now, in modified forms, employed in most pianos. Pianos are found in many forms, however, they are generally comprised of a frame, strings, a sound board, casing and wrest plank, and the action. The action consists of a system of levers whereby when a key is pushed, the hammers are actuated to strike the piano strings. The strike of the hammer against the string causes the string to vibrate and, consequently, produces sound. A piano's sound can be divided in two parts; loudness, which depends upon the amplitude of the vibration--determined by the power with which the hammer strikes the string--and the pitch, which depends upon the frequency of the vibration--determined by the diameter, length, and tautness of the string. In order for the piano to create pleasing sounds, the strings must be tuned such that harmonic vibrations and harmonic series are formed.
To produce sounds that are in tune, clear and precise without fouling other strings, the hammers must be flat with sharp edges. In order to shape the piano hammers (also referred to as "voicing" or "dressing" the hammers), technicians must smooth out ridges and grooves that develop in the hammers. Ideally, the hammers should have square shoulders with flat even strike points (crown) and a symmetrical shape.
Felt is commonly used to create the striking surface of the hammers. However, the hammers may vary in structure and materials used in their construction. The construction design of piano hammers is based upon initial cost, upkeep cost durability, and aesthetic characteristics (i.e. characteristics of the sound created upon operation).
A common problem encountered during the use of conventional tools and methods to shape or voice the hammers, is that the hammer are incorrectly shaped. Technicians accidently shape the hammers at an angle, or leave a rounded or lipped edge on the hammer. Additionally, it is difficult for technicians to shape each hammer in a desired form, or in a form that is consistent from one hammer to the next. These problems are due, in part to variances in the way tools are held and applied to the hammers, as well as most of the work being done "free hand." The shape of the hammer affects the sound characteristics produced by the piano, therefore it is desirable to have consistent, ideally shaped piano hammers. Finally, even when the technician is able to correctly shape the hammer, it is a time intensive process.
Thus, there is a need for a tool which a) correctly and accurately dresses piano hammers, b) dresses hammers in a consistent fashion, and c) reduces the amount of time needed to adequately dress the hammers.